Exogenous Ethephon Research Articles

Analysis of Ethylene Signal Regulating Sucrose Metabolism in Strawberry Fruits Based on RNA-seq.

Ethylene is a key hormone that regulates the maturation and quality formation of horticultural crops, but its effects on non-respiratory climacteric fruits such as strawberries are not yet clear. In this study, strawberry fruits were treated with exogenous ethephon (ETH) and 1-methylcyclopropene (1-MCP). It was found that ETH treatment increased the soluble solids and anthocyanin content of the fruits, reduced hardness, and decreased organic acid content, while 1-MCP treatment inhibited these processes. Transcriptome analysis revealed that differentially expressed genes (DEGs) were enriched in the starch-sucrose metabolism pathway. qRT-PCR results further showed significant changes in the expression levels of sucrose metabolism genes, confirming the influence of ethylene signals on soluble sugar accumulation during strawberry fruit development. This study elucidates the quality changes and molecular mechanisms of ethylene signal in the development of strawberry fruits, providing some key targets and theoretical support for guiding strawberry cultivation and variety improvement.

The MpNAC72/MpERF105-MpMYB10b module regulates anthocyanin biosynthesis in Malus 'Profusion' leaves infected with Gymnosporangium yamadae.

Apple rust is a serious fungal disease affecting Malus plants worldwide. Infection with the rust pathogen Gymnosporangium yamadae induces the accumulation of anthocyanins in Malus to resist rust disease. However, the mechanism of anthocyanin biosynthesis regulation in Malus against apple rust is still unclear. Here, we show that MpERF105 and MpNAC72 are key regulators of anthocyanin biosynthesis via the ethylene-dependent pathway in M. 'Profusion' leaves under rust disease stress. Exogenous ethephon treatment promoted high expression of MpERF105 and MpNAC72 and anthocyanin accumulation in G. yamadae-infected M. 'Profusion' leaves. Overexpression of MpERF105 increased the total anthocyanin content of Malus plant material and acted by positively regulating its target gene, MpMYB10b. MpNAC72 physically interacted with MpERF105 in vitro and in planta, and the two form a protein complex. Coexpression of the two leads to higher transcript levels of MpMYB10b and higher anthocyanin accumulation. In addition, overexpression of MpERF105 or MpNAC72 enhanced the resistance of M. 'Profusion' leaves to apple rust. In conclusion, our results elucidate the mechanism by which MpERF105 and MpNAC72 are induced by ethylene in G. yamadae-infected M. 'Profusion' leaves and promote anthocyanin accumulation by mediating the positive regulation of MpMYB10b expression.

Exogenous Activation of the Ethylene Signaling Pathway Enhances the Freezing Tolerance of Young Tea Shoots by Regulating the Plant’s Antioxidant System

Tea plants (Camellia sinensis (L.) O. Kuntze) frequently suffer severe damage as a result of freezing temperatures in early spring, which severely affect tea quality and tea production in China. Emerging evidence has demonstrated that the ethylene signaling pathway plays an important role in tea plants’ freezing responses. However, how ethylene modulates the response to freezing in sprouting tea shoots is not clear. This study verified that the measurement of relative electrolyte leakage in young shoots after 1 h at −5 °C is a rapid way to evaluate their freezing tolerance in the laboratory. Further exploration of the mechanism involved in increasing tea-shoot freezing tolerance by monitoring changes in the transcription of ethylene-related genes and cold signaling-related genes, and the physiological and biochemical changes after the application of ethephon (2-chloroethylphosphonic acid, an ethylene release reagent), revealed that exogenous ethephon significantly increased the freezing tolerance of tea shoots within 3 days of treatment, while concomitantly altering the expression of the ethylene signaling pathway-related genes (i.e., CsETR1, CsETR2, and CsEBF1). Moreover, antioxidant enzyme activities, including superoxide dismutase, catalase, and peroxidase, were uniformly upregulated, which might constitute a major physiological change induced by ethylene signaling and may be responsible for the observed increase in freezing resistance. Nevertheless, soluble sugars and starch, trehalose metabolism, and cold signaling-related genes did not appear relevant to the freezing tolerance increase following ethephon application. This study demonstrated that the freezing tolerance of sprouting tea shoots can be rapidly increased by the exogenous activation of the ethylene signaling pathway and upregulation of the plant’s antioxidant system.

Ethephon promotes isoflavone accumulation in germinating soybeans by its acceleration of isoflavone biosynthetic pathway

Soybeans have medicinal value and are an oil crop with medicinal and food properties. The present work investigated two aspects of isoflavone accumulation in soybean. First, germination conditions for exogenous-ethephon-mediated accumulation of isoflavone were optimised through response surface methodology. Second, various influences of ethephon on the growth of germinating soybeans and isoflavone metabolism were investigated. The findings of the research led to the conclusion that exogenous ethephon treatment effectively facilitated the enrichment of isoflavones in soybeans during germination. Optimal germination conditions were obtained through a response surface optimization test, which yielded the following criteria: a germination time of 4.2 d, an ethephon concentration of 102.6 μM, and a germination temperature of 30.2 °C. The maximum isoflavone content was 544.53 μg/sprout FW. Relative to the control, the addition of ethephon significantly inhibited sprout growth. Exogenous ethephon treatment led to the phenomenon that peroxidase, superoxide dismutase, and catalase activities and their gene expression increased significantly in germinating soybeans. Meanwhile, the expression of genes related to ethylene synthetase increase under the effect of ethephon promoting ethylene synthesis. Ethylene multiplied the total flavonoid content of soybean sprouts relying on the increase in activity and gene expression of crucial isoflavone biosynthesis-related enzymes (phenylalanine ammonia-lyase and 4-coumarate coenzyme A ligase) during germination.

Peroxynitrite is essential for aerenchyma formation in rice roots under waterlogging conditions

In this study, we report that peroxynitrite is necessary for ethylene-mediated aerenchyma formation in rice roots under waterlogging conditions. Plants under waterlogging stress face anoxygenic conditions which reduce their metabolism and induce several adaptations. The formation of aerenchyma is of paramount importance for the survival of plants under waterlogging conditions. Though some studies have shown the involvement of ethylene in aerenchyma formation under waterlogging conditions, the implication of peroxynitrite (ONOO-) in such a developmental process remains elusive. Here, we report an increase in aerenchyma formation in rice roots exposed to waterlogging conditions under which the number of aerenchyma cells and their size was further enhanced in response to exogenous ethephon (a donor of ethylene) or SNP (a donor of nitric oxide) treatment. Application of epicatechin (a peroxynitrite scavenger) to waterlogged plants inhibited the aerenchyma formation, signifying that ONOO- might have a role in aerenchyma formation. Interestingly, epicatechin and ethephon co-treated waterlogged plants were unable to form aerenchyma, indicating the necessity of ONOO- in ethylene-mediated aerenchyma formation under waterlogging conditions. Taken together, our results highlight the role of ONOO- in ethylene-mediated aerenchyma formation in rice and could be used in the future to develop waterlogging stress-tolerant varieties of rice.

Enhancing the accumulation of linoleic acid and α-linolenic acid through the pre-harvest ethylene treatment in Camellia oleifera.

Camellia oleifera Abel. (C. oleifera) is an important woody edible oil tree species in China. The quality of C. oleifera oil (tea oil) is mainly determined by the contents of linoleic acid (LA) and α-linolenic acid (ALA). However, how to increase the contents of LA and ALA in tea oil and the corresponding regulating mechanism have not been clarified. In the present study, we found that the LA and ALA contents in C. oleifera seeds were significant positively associated with the concentrations of ethephon and were decreased by ethylene inhibitor treatment. Furthermore, 1.5g L-1 ethephon could receive an optimal LA and ALA contents without adverse effects to the growth of 'Huashuo' trees in this study. The ethephon treatment also increased the contents of 1-aminocyclopropane-1-carboxylic acid (ACC), sucrose, soluble sugar and reducing sugar contents in seeds. Transcriptome analysis further suggested that exogenous ethephon application enhanced the accumulation of LA and ALA via regulating genes involved in LA and ALA metabolism, plant hormone signal transduction pathways, and starch and sucrose metabolism. Our findings confirm the role of ethylene in LA and ALA regulation and provide new insights into the potential utilization of ethylene as a LA and ALA inducer in C. oleifera cultivation.

Caspase 3-like protease is involved in ethylene-induced programmed cell death during aerenchyma formation in Helianthus annuus stem.

Previous research has reported that hypoxic conditions and ethylene treatments greatly trigger programmed cell death (PCD) occurrence and induce the formation of aerenchyma to adapt stress environment in Helianthus annuus stem. Caspase 3-like protease (CLP) as regulatory signals, also be involved in the process of PCD to adapt the low oxygen environment. However, the relationships between ethylene and CLP have seldom been reported. Herein, To understand the regulatory role of ethylene and CLP signaling molecules in aerenchyma formation, we investigated the effects of exogenous ethephon (ET), ethylene perception inhibitor 1-methylcyclopropene (1-MCP), and the treatment of 1-MCP + ET on morphological, physiological characteristics and aerenchyma formation in H. annuus stem. The results showed that lysigenous aerenchyma formation in H. annuus stem is induced by ET, and immunohistochemistry assay indicate CLP activity is raised at the formation stage of aerenchyma formation, and decreased at the expanding phase of aerenchyma formation. Western blotting illustrate the expression of CLP is also increased within 8h after ethylene signaling inducing aerenchyma formation, and the activities of CLP are higher in ET treated seedlings than the control and 1-MCP treated seedlings. The same phenomenon was also observed by caspase-3 activity assay. These results revealed there is a causal and interdependent relationship between ET and CLP signaling during the process of aerenchyma formation, which regulating PCD initiation in H. annuus stem.

Exogenous application of ethephon regulates flower abscission, shoot growth, and secondary metabolites in Camellia sinensis

Tea plant (Camellia sinensis (L.) O. Kuntze) consumes a large amount of nutrients and water during the flowering stage, which compromises the tea growth and yield. Ethylene is an important plant hormone that plays pivotal roles in regulating plant growth and flowering. but there are few studies on flowering and growth of tea plants regulated by this plant hormone. Here, we investigated the effects of exogenous ethephon application on the abscission of flowers and flower buds in tea plants. The results showed that application of ethephon induced the production of endogenous ethylene and the peak of ethylene production occurred three days post ethephon spraying on the tea plants. Ethephon treatment induced the abscission of tea flowers and flower buds, leading to reduced amount of flowers in the tea plantations. Ethylene receptors (ETRs) play critical roles in ethylene-mediated cellular responses, and we found that there was a certain correlation between the effect of ethephon on the flower abscission and the expression of several CsETRs, including CsETR3, CsETR4, CsETR5, and CsETR6. Ethephon also induced the high activities of superoxide dismutase, peroxidase, and catalase three days after treatment. In addition, ethephon obviously reduced the tea polyphenol content and enhanced the caffeine content in tea plants. Treatment with ethephon (3000 mg L–1) significantly increased tea shoot length and production in the tea plantations in the following early spring. Overall, ethephon, in a range of concentrations, could effectively suppress the tea plant blooming and improve tea yield and quality to a certain extent.

Metabolic and Transcriptomic Analyses Reveal the Effects of Ethephon on Taraxacum kok-saghyz Rodin

The roots of Taraxacum kok-saghyz Rodin (TKS) are well-known and valued for their rubber-producing ability. Therefore, research on the analysis and detection of metabolites from the roots of TKS have been reported in previous studies. However, all of these studies have the shortcoming of focusing on only the rubber of TKS, without profiling the other metabolites in a systematic and comprehensive way. Here, the primary and secondary metabolites from the leaves of TKS were investigated using UPLC–ESI–MS/MS, and a total of 229 metabolites were characterized. Carboxylic acid derivatives, fatty acyls, phenols, and organooxygen compounds were found to be the major metabolites of TKS. The transcriptome data indicated that ribosomal, glycolysis/gluconeogenesis, phenylpropanoid biosynthesis, and linoleic acid metabolism genes were significantly differentially expressed. This study is the first to report the differences in the metabolic and transcriptome profiles of TKS leaves under exogenous ethephon spray, which improves our understanding of the main metabolites and their molecular mechanisms in TKS leaves.

Distinct metabolic profiling is correlated with bisexual flowers formation resulting from exogenous ethephon induction in melon (Cucumis melo L.).

Melon (Cucumis melo L.) is an agronomically important vegetable. Most cultivars of melon are andromonoecious and bisexual flowers only emerged from the leaf axil of lateral branches. However, the regulatory mechanism contributing to the occurrence of bisexual flowers were still obscure. In this study, ethephon was applied in two common cultivars of melon. In control without ethephon treatment, no bisexual flower was made in the main stem. However, 6.56 ± 1.42 and 6.63 ± 0.55 bisexual flowers were respectively induced in main stem of ‘Yangjiaocui-QX’ and ‘Lvbao’ after ethephon treatment, and induced bisexual flowers distributed in 12–20 nodes of main stem. During the formation of bisexual flowers, 41 metabolites were significantly up-regulated and 98 metabolites were significantly down-regulated. According to the KEGG enrichment analysis of 139 different metabolites, a total of 30 pathways were mapped and KEGG terms of “Phenylalanine, tyrosine and tryptophan biosynthesis”, “Phenylalanine metabolism” and “Flavone and flavonol biosynthesis” were significantly enriched. In three significantly enriched KEGG terms, shikimic acid, L-tryptophan, L-phenylalanine, and kaempferol were significantly up-regulated while L-tyrosine, 4-hydroxycinnami acid and luteolin were significantly down-regulated in ET compared to CK. Different metabolites were also classified depend on major class features and 14 classes were acquired. The results of metabonomics and endogenous hormone identification indicated that ethylene could enhance the concentration of salicylic acid, methyl jasmonate, ABA and IAA. This study provided an important theoretical foundation for inducing bisexual flowers in main stem and breeding new varieties of melon in future.

Transcriptome and metabolite integrated analysis reveals that exogenous ethylene controls berry ripening processes in grapevine

Although grapevine (Vitis vinifera L.) is generally classified as a non-climacteric fruit, the regulatory mechanisms of ethylene in the ripening of non-climacteric fruit are still poorly understood. In this study, exogenous ethephon (ETH) strongly stimulated fruit color and anthocyanin accumulation, which was consistent with the increased expression of anthocyanin structural, regulatory, and transport genes. ETH application increased ABA content and decreased IAA content by coordinating ABA and auxin biosynthesis regulatory network. ETH treatment also accelerated sugar (glucose and fructose) accumulation by enhancing the gene expression involved in sugar transport and sucrose cleavage. ETH treatment blocked the synthesis of cellulose and accelerated the degradation of pectin, which was strongly associated with berry softening. To further confirm the function of ethylene biosynthesis and signaling genes, transient overexpression of VvACO4 and VvEIL3 were performed in both in tomato and strawberry fruits. These findings of the ethylene cascade add to our understanding of ethylene in non-climacteric berry ripening regulation and revealed a complex involvement of ethylene and its interplay with phytohormones during grapevine berry ripening.

Systematic genome-wide analysis of the ethylene-responsive ACS gene family: Contributions to sex form differentiation and development in melon and watermelon.

Ethylene is an important regulatory phytohormone for sex differentiation and flower development. As the rate-limiting enzyme encoding genes in ethylene biosynthesis, ACS gene family has been well studied in cucumber; however, little is known in other cucurbit crops, such as melon and watermelon, which show diverse sex types in the field. Here, we identified and characterized eight ACS genes each in the genomes of melon and watermelon. According to the conserved serine residues at C-terminal, all the ACS genes could be characterized into three groups, which were supported by the exon-intron organizations and conserved motif distributions. ACS genes displayed diverse tissue-specific expression patterns among four melon and three watermelon sex types. Furthermore, a comparative expression analysis in the shoot apex identified orthologous pairs with potential functions in sex determination, e.g., ACS1s and ACS6s. All ACS orthologs in melon and watermelon exhibited similar expression patterns in monoecious and gynoecious genotypes, except for ACS11s and ACS12s. As expected, the majority of ACS genes were responsive to exogenous ethephon; however, some orthologs exhibited opposite expression patterns, such as ACS1s, ACS9s, and ACS10s. Collectively, our findings provide valuable ACS candidates related to flower development in various sex types of melon and watermelon.

Effects of ethylene on berry ripening and anthocyanin accumulation of 'Fujiminori' grape in protected cultivation.

Although the grape berries are deliberated as a non-climacteric fruit, ethylene seems to be involved in grape berry ripening. However, the precise role of ethylene in regulating the ripening of non-climacteric fruits is poorly understood. Exogenous ethephon (ETH) can stimulate the concentration of internal ethylene and accelerate the accumulation of anthocyanins in berries of 'Fujiminori', including malvidin-, delphinidin-, and petunidin-derivatives (3',4',5'-trihydroxylated anthocyanins) and cyanidin-derivatives (3',4'-dihydroxylated anthocyanins). The content of 3',4',5'-trihydroxylated anthocyanins was extremely higher than 3',4'-dihydroxylated anthocyanins, and ethylene did not affect the composition of anthocyanins in grape. Furthermore, we observed the expression of anthocyanin structural and regulatory genes as well as ethylene biosynthesis and response genes in response to ETH treatment. The anthocyanins accumulation is significantly associated with increased expression of anthocyanin structural (VvPAL, Vv4CH, VvCHS, VvCHI, VvF3H, and VvUFGT) and regulatory genes (VvMYBA1, VvMYBA2, and VvMYBA3), which persisted over the 12 days. In addition, exogenous ETH affected the endogenous ethylene biosynthesis (VvACO2 and VvACO4) and the downstream ethylene regulatory network (VvERS1, VvETR2, VvCTR1, and VvERF005). These findings bring new insights into the physiological and molecular function of ethylene during berry development and ripening in grapes. © 2021 Society of Chemical Industry.

Ethylene-regulated immature fruit abscission is associated with higher expression of CoACO genes in Camellia oleifera.

Immature fruit abscission is a key limiting factor in Camellia oleifera Abel. (C. oleifera) yield. Ethylene is considered to be an important phytohormone in regulating fruit abscission. However, the molecular mechanism of ethylene in regulating fruit abscission in C. oleifera has not yet been studied. Here, we found that the 1-aminocyclopropane-1-carboxylic acid (ACC) content was significantly increased in the abscission zones (AZs) of abnormal fruits (AF) which were about to abscise when compared with normal fruits (NF) in C. oleifera ‘Huashuo’. Furthermore, exogenous ethephon treatment stimulated fruit abscission. The cumulative rates of fruit abscission in ethephon-treated fruits (ETH-F) on the 4th (35.0%), 8th (48.7%) and 16th (57.7%) days after treatment (DAT) were significantly higher than the control. The ACC content and 1-aminocyclopropane-1-carboxylate oxidase (ACO) activity in AZs of ETH-F were also significantly increased when compared with NF on the 4th and 8th DAT. CoACO1 and CoACO2 were isolated in C. oleifera for the first time. The expressions of CoACO1 and CoACO2 were considerably upregulated in AZs of AF and ETH-F. This study suggested that ethylene played an important role in immature fruit abscission of C. oleifera and the two CoACOs were the critical genes involved in ethylene's regulatory role.

Transcriptome analysis reveals ethylene-mediated defense responses to Fusarium oxysporum f. sp. cucumerinum infection in Cucumis sativus L.

BackgroundFusarium wilt, caused by Fusarium oxysporum f. sp. cucumerinum (Foc), is a severe disease affecting cucumber (Cucumis sativus L.) production worldwide, but mechanisms underlying Fusarium wilt resistance in cucumber remain unknown. To better understand of the defense mechanisms elicited in response to Foc inoculation, RNA sequencing-based transcriptomic profiling of responses of the Fusarium wilt-resistant cucumber line ‘Rijiecheng’ at 0, 24, 48, 96, and 192 h after Foc inoculation was performed.ResultsWe identified 4116 genes that were differentially expressed between 0 h and other time points after inoculation. All ethylene-related and pathogenesis-related genes from the differentially expressed genes were filtered out. Real-time PCR analysis showed that ethylene-related genes were induced in response to Foc infection. Importantly, after Foc infection and exogenous application of ethephon, a donor of ethylene, the ethylene-related genes were highly expressed. In response to exogenous ethephon treatment in conjunction with Foc inoculation, the infection resistance of cucumber seedlings was enhanced and endogenous ethylene biosynthesis increased dramatically.ConclusionCollectively, ethylene signaling pathways play a positive role in regulating the defense response of cucumber to Foc infection. The results provide insight into the cucumber Fusarium wilt defense mechanisms and provide valuable information for breeding new cucumber cultivars with enhanced Fusarium wilt tolerance.

Identification and Characterization of a Potential Candidate Mlo Gene Conferring Susceptibility to Powdery Mildew in Rubber Tree.

Mildew resistance locus O (Mlo) gene was first found in barley as a powdery mildew susceptibility gene, and recessive mlo alleles confer durable resistance to barley powdery mildew. To identify candidate Mlo susceptibility genes in rubber tree, HbMlo12 was cloned from rubber tree clone CATAS7-33-97, which is susceptible to powdery mildew. Protein architecture analysis showed that HbMlo12 was a typical Mlo protein with seven transmembrane domains. Protein blast search in the Arabidopsis thaliana proteome database showed that HbMlo12 shared the highest similarity with AtMlo12, with 63% sequence identity. Furthermore, HbMlo12 together with the dicot powdery mildew susceptible Mlo proteins (including AtMlo2, AtMlo6, AtMlo12, tomato SlMlo1, pepper CaMlo2, pea PsMlo1, etc.) were grouped into clade V. Subcellular localization analysis in tobacco epidermal cells revealed that HbMlo12 was localized to the endoplasmic reticulum membrane. HbMlo12 was preferentially expressed in the flower and leaf of rubber tree. Moreover, its expression was significantly upregulated in response to powdery mildew inoculation. Application of exogenous ethephon caused a distinct increase in HbMlo12 expression. Additionally, HbMlo12 transcript was quickly induced by spraying salicylic acid and gibberellic acid and reached the maximum at 0.5 h after treatments. By contrast, HbMlo12 expression was downregulated by methyl jasmonate, abscisic acid, and drought stress treatments. There was no significant change in HbMlo12 expression after indole-3-acetic acid, H2O2, and wounding stimuli. Taken together, these results suggested that HbMlo12 might be a candidate Mlo gene conferring susceptibility to powdery mildew in rubber tree. The results of this study are vital in understanding Mlo gene evolution and developing new rubber tree varieties with powdery mildew resistance using reverse genetics.

Aminocyclopropane-1-carboxylic acid is a key regulator of guard mother cell terminal division in Arabidopsis thaliana.

Stomata have a critical function in the exchange of gases and water vapor between plants and their environment. Stomatal development is under the rigorous control of many regulators. The last step of development is the terminal division of guard mother cells (GMC) into two guard cells (GC). It is still unclear how the symmetric division of GMCs is regulated. Here, we show that the ethylene precursor aminocyclopropane-1-carboxylic acid (ACC) is required for the symmetric division of GMCs into GCs in Arabidopsis. Exogenous application of the ACC biosynthesis inhibitor aminoethoxyvinylglycine (AVG) induced the formation of single guard cells (SGCs). Correspondingly, an acs octuple-mutant with extremely low endogenous ACC also developed SGCs, and exogenous ACC dramatically decreased the number of SGCs in this mutant whereas exogenous ethephon (which is gradually converted into ethylene) had no effect. Furthermore, neither blocking of endogenous ethylene synthesis nor disruption of ethylene signaling transduction could induce the production of SGCs. Further investigation indicated that ACC promoted the division of GMCs in fama-1 and flp-1myb88 mutants whereas AVG inhibited it. Moreover, ACC positively regulated the expression of CDKB1;1 and CYCA2;3 in the fama-1 and flp-1myb88 mutants. The SGC number was not affected by ACC or AVG in cdkb1;11;2 and cyca2;234 mutants. Taken together, the results demonstrate that ACC itself, but not ethylene, positively modulates the symmetric division of GMCs in a manner that is dependent on CDKB1s and CYCA2s.

Abscisic acid and ethephon treatments applied to ‘Verdejo’ white grapes affect the quality of wine in different ways

ABSTRACT: Exogenous ethephon and abscisic acid (ABA) treatments are used worldwide to improve the coloring of red table grapes, but there is little information about their impact on the quality of white grapes and wines. The aim of this work was to evaluate the effects of exogenous ethephon and ABA applications at veraison on the composition of ‘Verdejo’ white grapes, and on the quality of their wines. To attain this objective, a field trial was carried out in a ‘Verdejo’/110 Richter vineyard located in north-central Spain. Two levels of ethephon (0 and 1500 mg L−1) and ABA (0 and 800 mg L−1) were sprayed on clusters at veraison, in a factorial design for three consecutive seasons. Ethephon and ABA had additive effects, decreasing titratable acidity and increasing pH of the must, which could be exploited by accelerating the grape ripening process in cold-climate zones. Nevertheless, each growth regulator affected the composition and sensory analysis of the wines differently. Ethephon treatments produced wines with lower concentration of acids and better flavor quality than those made from untreated plants, while wines with ABA applications tended to have a higher ethanol concentration and poorer aroma quality than controls. The wines submitted to treatments with ethephon obtained the best overall evaluation in the sensory analysis throughout the trial.

Constitutive Expression of Aechmea fasciata SPL14 (AfSPL14) Accelerates Flowering and Changes the Plant Architecture in Arabidopsis.

Variations in flowering time and plant architecture have a crucial impact on crop biomass and yield, as well as the aesthetic value of ornamental plants. Aechmea fasciata, a member of the Bromeliaceae family, is a bromeliad variety that is commonly cultivated worldwide. Here, we report the characterization of AfSPL14, a squamosa promoter binding protein-like gene in A. fasciata. AfSPL14 was predominantly expressed in the young vegetative organs of adult plants. The expression of AfSPL14 could be upregulated within 1 h by exogenous ethephon treatment. The constitutive expression of AfSPL14 in Arabidopsis thaliana caused early flowering and variations in plant architecture, including smaller rosette leaves and thicker and increased numbers of main inflorescences. Our findings suggest that AfSPL14 may help facilitate the molecular breeding of A. fasciata, other ornamental and edible bromeliads (e.g., pineapple), and even cereal crops.

Molecular characterization and expression analysis of two farnesyl pyrophosphate synthase genes involved in rubber biosynthesis in Hevea brasiliensis

Farnesyl pyrophosphate synthase (FPS) catalyzes the formation of farnesyl pyrophosphate from dimethylallyl pyrophosphate, which is an important precursor of terpenoids, such as polyisoprenoid, in rubber-producing plants. In this paper, two genes encoding FPSs, FPS1 and FPS2, were isolated from Hevea brasiliensis using PCR. The full-length cDNAs of HbFPS1 and HbFPS2 are 1320 and 1324bp, respectively; both contain 1026-bp open reading frames that encode a polypeptide of 342 amino acid residues. They share 87% and 83% (HbFPS1), and 78% and 78% (HbFPS2) amino acid identities with the FPSs of Eucommia ulmoides and Parthenium argentatum, respectively. There is a 91% amino acid identity between HbFPS1 and HbFPS2. HbFPSs prefer T-ended codons for amino acids and have a strong asymmetric mutation bias. The genomic sequences of HbFPS1 and HbFPS2 are 7799 and 11,345bp, respectively, both comprising 12 exons and 11 introns. The HbFPS promoters contain multiple cis-regulatory elements involved in responsiveness to light, hormones and stress. Quantitative RT-PCR analyses showed that HbFPS mRNAs were present in all of the organs of mature virgin rubber plants, but their transcripts were most abundant in the reproductive organs. High expression levels of individual genes in the leaf levels of young shoots at particular positions suggested important roles for laticifer differentiation in different phases of stem bark development. HbFPS expression levels were significantly upregulated in the latex after bark tapping and exogenous ethephon or methyl jasmonate treatments. Both genes were upregulated in the latex of severely tapping panel dryness-affected trees but were downregulated in the latex from healthy and slightly affected bark. Thus, the two HbFPS genes may play essential roles in cis-1,4-polyisoprene synthesis in rubber trees, which would provide the basis for their further functional dissection.